D.1. In the intensive care unit (ICU) 4 hours later, the patient became hypotensive with a low cardiac output. How could you distinguish between cardiac tamponade and pump failure? How would the TEE images differ?
Answer:
Differentiation between cardiac tamponade and primary pump failure in the immediate post-bypass ICU setting can be difficult. Elevations in filling pressures, systemic hypotension, and low cardiac output are consistent with both diagnoses. The classic finding of equalization of intracardiac diastolic pressures might not be present because areas of focal compression from clot or focal effusion can markedly reduce filling of only one chamber in the absence of an intact pericardium. Echocardiography enables visualization of pericardial effusions and chamber volume and function. Diffuse or focal compression of the cardiac chambers from pericardial clot or effusion can readily be distinguished from a volume-overloaded, failing heart with poor myocardial contractility. Atrial collapse during ventricular systole with subsequent ventricular diastolic collapse is diagnostic of tamponade. TEE can be indicated, as TTE windows are frequently obscured by dressings, pacing pads, and drainage tubes. When the diagnosis is not clear, surgical reexploration can be necessary. (See Chapter 12: Cardiac Tamponade.)
References
- Bojar RM. Mediastinal bleeding. In: Bojar RM, ed. Manual of Perioperative Care in Adult Cardiac Surgery. 6th ed. John Wiley & Sons; 2021:417-456.
- Leiva EH, Carreño M, Bucheli FR, et al. Factors associated with delayed cardiac tamponade after cardiac surgery. Ann Card Anaesth. 2018;21:158-166.
- Society of Thoracic Surgeons Task Force on Resuscitation After Cardiac Surgery. The Society of Thoracic Surgeons expert consensus for the resuscitation of patients who arrest after cardiac surgery. Ann Thorac Surg. 2017;103:1005-1020.